Logging represents the most dangerous occupation in the United States, retaining the highest fatality and injury rates. Usual steep slope logging operation can be divided into four components: falling of the tree stem, yarding the tree stem to the landing, unhooking of the tree stem at the landing, and manufacturing the tree stem into the appropriate log lengths. While log manufacturing has long been overtaken by mechanized equipment, the first three components (i.e., falling, yarding, and unhooking) are still manually performed on steep slopes by timber fallers, choker setters and chasers, the respective most hazardous jobs in logging. The main goal of this study is therefore to develop guidelines for innovative logging systems that can eliminate or reduce the needs of such high risk manual activities during steep slope logging operations. Four specific aims are proposed, including a (1) demonstration of new mechanized logging systems with industry cooperators; (2) assessment of practical and physiological response of workers during operation; (3) develop design guidelines and criteria for new logging systems; and (4) deliver outreach and educational components to people in the logging occupation. This multi-dimensional project seeks adoption of improved safety practices by the logging industry and development of rules for safe application of mechanized steep slope logging by policy-makers. When the study is completed, we will have (1) evaluated the benefits of mechanical falling and bunching on safe operation, (2) extended the applications of grapple yarding and cable-assisted vehicles to reduce exposure to hazards, (3) documented the improved safety of the new systems using a variety of quantitative techniques, and (4) developed multi-media outreach programs to support the adoption of the improved safety techniques developed in this study. The project addresses the NIOSH Agriculture, Forestry and Fishing (AgFF) Strategic Goal 6: Reduce the number, rate and severity of traumatic injuries and deaths involving hazards of forestry. More specifically, this study aligns with Action Step 6.1.4: Determine what approaches or studies might be needed to fill gaps in information needed for developing and testing new interventions, including engineering, information technology, guidelines and policies. Implement trials for improved data collection and review potentials for improvements.